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Effects Of Carbon-rich Silicon Fertilizer Application On Greenhouse Gases Emissions And Microbial Community Structure In Paddy Fields

Posted on:2021-07-01Degree:MasterType:Thesis
Country:ChinaCandidate:X T WangFull Text:PDF
GTID:2480306515993419Subject:Microbiology
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In order to explore the effects of applying carbon-rich silicon fertilizer on paddy soil environmental factors,carbon pool composition,iron metabolism,microbial community structure and its correlation with greenhouse gas emissions such as CO2,CH4,and N2O from paddy fields,this study took a plain paddy field in Fuzhou as a test site,before the rice seedlings were transplanted,three kinds of carbon-rich silicon fertilizers(300,600,900kg/ha)were amended.Physical and chemical properties,nutrient content,soil iron metabolism,and greenhouse gas emissions were analyzed in the early and late paddy growing seasons under the application of carbon-rich silicon fertilizers.Moreover,bacterial and archaea diversity,community structure,and composition were also measured by high-throughput sequencing method.Pearson correlation was used to analyze the effect of various factors on greenhouse gas emissions from paddy fields.The main findings are as follows:1.The application of carbon-rich silicon fertilizer could promote the seed setting rate of paddy,which was beneficial to the increase of paddy yield.Paddy soil water content,bulk density and electrical conductivity were mainly affected by time-regulated natural precipitation and artificial water management.Paddy soil water content and bulk density were significantly different at different time conditions(p<0.01).The effects of carbon-rich silicon fertilizer treatment and time on paddy field soil pH reached a significant level(p<0.01),which significantly increased the soil pH value.Different water management and precipitation at different growth stages of early and late paddy had certain effects on paddy field soil pH.The application of carbon-rich silicon fertilizer could regulate the soil nutrients in paddy fields.The three application treatments significantly increased the total carbon content of the late paddy at the mature stage and the total nitrogen content of the late paddy at the jointing stage,which significantly increased the total iron content of the late rice(p<0.05).2.The application of carbon-rich silicon fertilizer could significantly increase the total organic carbon content(SOC)of paddy soils.In addition,there was a certain correlation between the carbon content of paddy soils and greenhouse gas emissions.The CO2 and CH4emissions of early and late paddy were significantly affected by time(p<0.01).The application of carbon-rich silicon fertilizer could significantly reduce the CO2 emissions of early paddy.Compared with the control,the CO2 emissions of the 300 and 900kg/ha treatment groups were reduced by 17.43%and 27.58%,respectively(p<0.05).Inhibition of CH4 emission by treatment was more obvious in early paddy.Compared with the control,methane emissions from early paddy 600 and 900kg/ha treatment groups were reduced by37.30%and 44.10%respectively.The three application treatments significantly reduced N2O emissions from early paddy.Compared with the control,the treatment groups of 300,600,and 900 kg/ha carbon-rich silicon fertilizer were reduced by 78.08%,42.92%,and97.72%(p<0.05).3.The application of carbon-rich silicon fertilizer could affect the iron composition of the paddy soil and regulate the iron film content on the surface of paddy roots.And through correlation analysis,it could be known that iron metabolism in paddy soil was one of the important factors affecting greenhouse gas emissions.Both CH4 and CO2 emissions in paddy fields were significantly and negatively correlated with Fe(?)content in paddy soils.CH4 and CO2 emissions from late rice were significantly and negatively correlated.There was a significant positive correlation with the number of iron reducing bacteria in the paddy soil(p<0.05).4.According to the Shannon index,the application of different levels of carbon-rich silicon fertilizer increased the diversity of bacterial communities in early paddy and reduced the diversity of bacterial communities in late paddy,which was related to the different climatic environments of early and late paddy.A total of 46 bacterial phylums and 548 bacterial genera were identified during the jointing stage of early and late paddy.A total of 47bacterial phylums and 551 bacterial genera were identified during maturity.Proteobacteria,Firmicutes and Bacteroidetes and others are the dominant bacteria in the paddy soil of the Fuzhou Plain in the phylum level,and the dominant bacteria in different soil samples were different.The relatively abundant bacteria in genera level were Ignatzschineria and Stenotrophomonas.5.According to the?diversity index,the application of carbon-rich silicon fertilizer with different application amounts could change the archaea diversity in paddy fields,but the effects were not consistent.A total of 5 archaea and 46 archaea phylums were identified in the early and late paddy jointing stage,and 5 archaea and 29 archaea genera were identified in the mature stage.Among them,Euryarchaeota,Crenarchaeota,and Thaumarchaeota are the dominant archaea in the paddy field of the Fuzhou Plain in phylum level,Methanocella,Candidatus?Nitrosotalea,and Candidatus?Methanoperedens was the dominant archaea in the paddy field of Fuzhou Plain in genera level.6.Carbon-rich silicon fertilizer could change the relative abundance of bacteria in the soil by changing some physical and chemical properties of the soil and changes in living conditions,further changing the soil microbial community structure in the paddy field.The influence and regulation of climatic conditions during planting time and different growing seasons,and the change of soil microbial community structure were the result of the joint adjustment of these two factors.
Keywords/Search Tags:carbon-rich silicon fertilizer, greenhouse gases, environmental factors, soil microorganisms, paddy fileds
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